Commercial polymers based on the inclusion of carbonate units are well known (Lexan-General Electric and Makrolon-Bayer). These materials are thermoplastic (130.degree. C. processing temperature) and exhibit a high degree of impact resistance when they are maintained in an amorphous state. The polymers do lose their toughness as they crystallize. The polycarbonates have a heat distortion temperature in the range of 130.degree.-140.degree. and can withstand continuous use at temperatures up to 120.degree. C. These systems have always exhibited crazing and loss of properties when exposed to many organic solvents. Acetone is particularly deleterious to polycarbonates. Attempts to develop a more temperature and solvent-resistant polymers have led to the development of a series of polymers which contain both carbonate and imide units. This polymer class was synthesized because polyimides are known to afford excellent solvent resistance and to perform at elevated temperatures (W. M. Edwards, U.S. Pat. No. 3,179,634). Also the incorporation of thermoplastic, solvent-sensitive sulfone units into a polyimide backbone has resulted in a thermoplastic, solvent-resistant polymer (T. L. St. Clair and D. A. Yamaki, U.S. Pat. No. 4,398,021). However, neither of these polymers has the requisite properties desired for the present applications. Thus, there is a definite need in the art for an aromatic resin that can be cured between 180.degree.-300.degree. C. which exhibits improved solvent and thermal resistance.
Accordingly, an object of the present invention is to develop a series of poly(carbonate-imides) which can be processed between 180.degree.-300.degree. C. and exhibit a heat-distortion temperature above 140.degree. C.
Another object of the present invention is to develop a series of poly(carbonate-imides) with resistance to common organic solvents such as acetone.
Another object of the present invention is to develop a series of poly(carbonate-imides) which exhibits a high degree of order or crystallinity after the system has been heated above its heat distortion temperature.
Another object of the present invention is a novel process for preparing a carbonate-containing polymer which does not involve the use of the hazardous chemical phosgene.
Another object of the present invention is the preparation of novel carbonate-containing monomers for use in the preparation of the poly(carbonate-imides).
Another object of the present invention is a novel process for preparing the polymeric precursors to the poly(carbonate-imides) in a solvent system.
Another object of the present invention is a novel process for thermally eliminating solvent and reaction by-products in preparing the poly(carbonate-imides).